Allocated fixed costs, often called common costs, are costs that are not traceable to a particular product, service, product line, or segment. They are never relevant because the costs are assigned to a number of products.llocated fixed costs, often called common costs, are costs that are not traceable to a particular product, service, product line, or segment. They are never relevant because the costs are assigned to a number of products.
Definition of roost. 1  1a : a support on which birds restb : a place where winged animals and especially birds customarily roost. 2  2 : a group of birds roosting together.
the lair or shelter of a wild animal, especially a predatory mammal. 2. a room, often secluded, in a house or apartment, designed to provide a quiet, comfortable, and informal atmosphere for conversation, reading, writing, etc. 3. a cave used as a place of shelter or concealment. 4. a squalid or vile abode or place: dens of misery.